Question

1) Determine o valor de x na igualdade:

Answer 1

$\left[\begin{array}{ccc}x&4\\9&x\end{array}\right] = x^{2} -36= x^{2} =36 \\ \sqrt{ x^{2} } = \sqrt{36} \\ x = 6 \\ x = -6$

Portanto, x = 6

Alternativa: E)

Espero ter ajudado.

Answer 2

$\left[\begin{array}{ccc}x&4\\9&x\end{array}\right] =0~\to\\\\\\ x^2-36=0\to\\\\ x^2=36\to\\\\ x=\pm ~\sqrt{36} \to\\\\ x=\pm~6\\\\\\ \large\boxed{Resposta:Letra~~E)~6}$